Roasting apparatus

ABSTRACT

Apparatus for roasting particulate solids which includes a system for heating and circulating a fluid through a roasting vessel and arrangements for supplying material to be processed to and discharging it from the reactor.

United States Patent [191 Smith, Jr.

[ Oct. 9, 1973 ROASTING APPARATUS [75] Inventor: Horace L. Smith, Jr., Richmond,

[73] Assignee: Smitherm1ndustries,1nc.,

Richmond, Va.

[22] Filed: Oct. 30, 1972 [21] Appl. No.: 301,977

Related [15. Application Data [60] Continuation-impart of Ser. No. 279,748, Aug. 11, 1972, which is a division of Ser. No. 137,274, April 26, 1971, Pat. No. 3,730,731, and a continuation-in-part of Ser. No. 44,464, June 8, 1970, Pat. No. 3,615,668.

Primary Examiner-Wayne A. Morse, Jr. Attorney-William A. Strauch et a1.

57 3 ABSTRACT Apparatus for roasting particulate solids which includes a system for heating and circulating a fluid through a roasting vessel and arrangements for supplying material to be processed to and discharging it from the reactor.

9 Claims, 9 Drawing Figures [52] US. Cl 99/468, 99/469, 99/470, I 99/472, 99/475 [51] Int. Cl. A231 1/02, A23n 9/02, A23n 9/04 58] Field ofSearch ..99/468472,475,429

I98 216 268 mm 234\ 224 35 VESSEL :a-enm arms m 1 ROASTED arms 36/ 2s; PACKING BEAN STORAGE PATENTED 9 73 SHEEI 10F T 855mm tie PATENTED T 75 SHEET 30F 7 PAIENIEDIIIII 9191a 3.763.766 SHEEI I [1F 7 FIG 5 GREEN BEANS INTO FEED LOCK 2g EvAGuATE AIR FROM LOCK 24m 2 Hg PRESSURIZE LOCK 24 WITH N2 GREEN BEANS INTO oAsTER 22 VENT LOCK 2410 3D Hg N2 EVACUATE LOCK 24 1D 2' Hg N2 ROASTED BEANS INEO DISCHARGE LOCK 3o VENT LOCK 301030 Hg N2 EVACUATE LOCK 30 TO 2"R N2 m ROASTED BEANS INTO GDDLER 4 @222 EVACUATE AIR FROM LOOKBOTOZ Hg v II m PRESSURIZE LOCK 30 WITH N2 m INDEX RDTAIABLE ASSEMBLY 58' m ONEINCREMENT |II|IgII|I||||||IIII| CYCLE TIME-SECONDS VIII/111A PATENTED w 1 s SHEET 6 {IF 7 PATENTEDU 3.763.766

SHEET VUF 7 1 ROASTING APPARATUS This application is a continuation-in-part of copending Application Ser. No. 279,748'filed Aug. 11, 1972. Application Ser. No. 279,748 is a division of Application Ser. No. 137,247 filed Apr. 26, 1971 (now U.S. Pat. No. 3,730,731), which is a continuation-in-part of Application Ser. No. 44,464 filed June 8, 1970 (now -S. ato- 3.2 15633 The present invention relates in one aspect to the processing of particulate solids and, more specifically, to novel, improved apparatus for roasting coffee beans and comparably processable solids.

In another aspect the present invention relates to novel improved valves for use in apparatus of the character described in the preceding paragraph and for other applications as well.

Copending Application Ser. No. 279,748 discloses certain novel apparatus for roasting coffee and comparably processable solids which has a number of advantages over the roasting apparatus theretofore available. In the apparatus disclosed in that application, the solids to be processed are introduced into and discharged from a reactor or roasting vessel through devices designed to prevent the egress of roasting fluid and the ingress of air so that an atmosphere of controlled composition and/or an above-atmospheric pressure can be maintained in the reactor. As a result, the beans can be processed without oxidative degradation and, in the case of less expensive beans, under conditions which will materially upgrade their quality.

The solids thus introduced into the reactor are formed into a bed with successive increments of the introduced solids being confined to specific locations in the bed. This bed is displaced to move the solids from the location at which they are introduced to the location where they are discharged.

As the bed is displaced, the solids are roasted by a heated fluid, which will typically be an inertgas such as nitrogen. The roasting fluid is directed upwardly through the bed, typically through inclined apertures in a stationary nozzle plate located in the lower reaches of the reactor. This causes the solids being roasted to circulate in a pattern which produces uniform and intimate contact between the fluid and the particulate solids and a consequent uniform roasting of the solids.

In this previously disclosed apparatus the bed is alternately incrementally advanced and halted in moving the solids from the location at which they are introduced to the location where they are removed. This permits simple, gastight locks to be employed to introduce solids into the reaction vessel and to remove roasted solids therefrom.

The roasted solids in one segment of the bed are transferred therefrom while the bed is halted into the discharge lock. At the same time unroasted solids are transferred from the feed lock into the bed to replace the previously discharged segment.

Also, in preferred embodiments of the invention, air is evacuated from the locks and replaced with roasting fluid in an appropriate sequence; and the roasting fluid is then evacuated from the locks and returned to the fluid circulating system. This permits both the ingress of air into the roasting vessel and the loss of roasting fluid to be minimized.

Valves must be provided to control the transfer of solids into and from the feed and discharge locks of the roasting apparatus and to isolate the locks from the roasting vessel and/or the ambient surroundings while the locks are being evacuated and filled with and emptied of roasting fluid. Coffee beans and the chaff generated in the roasting process are abrasive and contributed to rapid deterioration of the conventional valves first employed in association with the feed and discharge locks of the roasting apparatus disclosed in Application Ser. No. 279,748 as did the roasting fluid which typically had a temperature of over 400F. Because of their short service life, the cost of replacements, and the downtime involved in replacing them, conventional valves proved unsatisfactory from an economic point-of-view.

In an effort to solve this problem, the originally used type of valve was replaced with one still of conventional design but constructed of more wear and temperature resistant materials. While this change resulted in longer service lifefthe cost of such valves in the sizes required for a full-scale commercial system proved to be prohibitive.

I have now invented certain novel valves of a unique construction which, even when made from conventional valve materials, have an almost indefinite service life although continuously exposed to coffee beans and chaff and to high temperature, high velocity gases. Because conventional materials are used in these valves and because of their simplicity, they are inexpensive, even in the large sizes needed for commercial scale coffee roasting installations.

Briefly, the novel valves I have invented include a valve body with an axially aligned inlet and outlet and an internal passage providing flow communication therebetween. A replaceable valve seat is mounted in the valve body at an angle to the flow passage, which is in part formed by a central aperture through the seat.

A valve stem supporting a loosely fitted valve member biased against an abutment on the stem is movable directly toward and away from the valve seat to close and open the valve by a fluid-actuated cylinder attached to the exterior of the valve body. By virtue of the manner in which the valve member is attached to the valve stem and a knife edge projection which can be formed on either the valve seat or the valve member, a high unit and uniform contact pressure can be developed between the valve member and valve seat to provide an exceptionally tight seal therebetween. This is true even though there may be foreign matter on the valve seat or valve member as foreign substances will simply be sheared by the knife edge as the valve member is seated.

The novel method of mounting the valve member on the valve stem also insures that a uniformly tight seal is obtained in circumstances where the valve stem and valve are not exactly concentric or in precise axial alignment.

An O-ring or comparable seal is deployed between the loosely fitting valve stem and valve member. This seal keeps fluid from leaking past the stem when the valve is closed, even though the valve member may be tilted relative to the stem.

Although originally developed for the purposes discussed previously, the novel valves just described can be used in a variety of applications including those for which the superficially similar valves disclosed in US. Pat. Nos. 20,314 issued May 25, 1858; 1,457,318 issued .lune 5, 1923; 2,098,696 issued Nov. 9,1937;

2,312,063 issued Feb. 23, 1943; 2,602,627 issued July,

8, 1952; 2,666,614 issued Jan. 19,1954; 2,720,219 issued Oct. 11, 1955; 2,829,664 issued Apr. 8, 1958; and 3,101,924 issued Aug. 27, 1963, are intended. My novel valves are especially well-suited for the handling of abrasive materials, for high temperature service, and for applications where tight seals are required.

Aside from those discussed above and attributable primarily to the use of the novel valves I have invented, the coffee roasting systems disclosed herein have the advantages of using relatively inexpensive sources of inert roasting fluids and a simple system for heating the roasting fluid. Also, the fluid circulation system is simple; and the moisture content of the roasting fluid can be regulated without venting fluid from the system. The last feature is important because it eliminates the loss of roasting fluid and sensible heat associated with venting, the hardware required for venting, and the hardware needed to eliminate pollutants from the vented fluid.

Further, the cyclic depressurization and repressurization associated with the unloading and loading of the reactor and other components in the fluid circulating system of batch-type apparatuses such as disclosed in my US Pat. Nos. 3,328,172 issued June 27, 1967; 3,328,894 and 3,329,506 issued July 4, 1967; 3,332,780 issued July 25, 1967; 3,345,180 and 3,345,181 issued Oct. 3, 1967; 3,385,199 issued May 28, 1968; 3,395,634 issued Aug. 6, 1968;-3,408,920 issued Nov. 5, 1968; and 3,447,338 issued June 3, 1969, is eliminated. The apparatus can consequently be made much simpler since the hardware needed to effect depressurization and repressurization is not required.

Still other advantages of the novel apparatus disclosed herein are that it provides uniform treatment of the solids being processed, versatility, accurate process control, a high rate of heat transfer, and reduced power requirements. At the same time these advantages can be achieved at lower cost and with relatively uncomplicated equipment.

One primary object of the present invention resides in the provision of novel, improved apparatus for roasting coffee beans and comparably processable solids.

A second and equally important object of the invention is the provision of novel, improved valves which are useful in a variety of applications and can be used to particular advantage in the coffee roasting system disclosed herein.

Other more specific but important objects of the invention include the provision of coffee roasting apparatus of the continuous type:

l.which produces a uniform product, is versatile, and

has high efficiency.

2. in which the solids can be roasted in an atmosphere of controlled composition or controlled composition and above-atmospheric pressure.

3. in which, in conjunction with the preceding object, gastight locks are employed in introducing solids to be roasted into a roasting vessel and in removing roasted solids from the vessel to keep air from entering the vessel and to prevent the escape of roasting fluid.

4. in which, in conjunction with the preceding object,

a bed of solids being roasted is alternately advanced and halted and in which the solids are intro- 6 duced into and removed from the bed while it is halted to thereby simplify the steps of introducing the solids into and removing them from the roasting vessel. Still other important objects of the present invention reside in the provision of novel, improved valves which:

5. have high wear resistance in the presence of abrasive materials.

6. are suited for high temperature service.

7. are capable of providing a tight seal even though foreign matter may be present on the valve seat or the valve member.

8. are particularly well-suited to controlling the flow of solids into and from the roasting vessel in a roasting system of the character described above.

Still other important objects and features and further advantages of the invention will become apparent from the appended claims and as theensuing detailed description and discussion proceeds in conjunction with the accompanying drawing, in which:

FIG. 1 shows the relationship between FIGS. 1A and 1B which together constitute a schematic illustration of a system or plant for roasting particulate solids, the plant being constructed in accord with the principles of the present invention and being designed specifically for coffee roasting;

FIG. 2 is a vertical section through the lower part of a reactor or roasting vessel employed in the system of FIG. 1;

FIG. 3 is a section through the roasting vessel of FIG. 2 to a reduced scale and is taken substantially along line 3-3 of the latter Figure;

FIG. 4 is a schematic illustration of an arrangement for rotating a movable assembly which is employed in the roasting vessel to displace a bed of solids being roasted;

FIG. 5 is a timing diagram for the operation of the coffee roasting system of FIG. 1;

FIG. 6 is a schematic of a hydraulic system employed to open and close certain sequentially operated valves employed in the system of FIG. 1;

FIG. 7 is a section through one form of valve in accord with the principles of the present invention; and

FIG. 8 is a section through a second form of valve in accord with the principles of my invention.

Referring now to the drawing, FIGS. 1A and 18 depict diagrammatically a coffee roasting plant or system 20 constructed in accord with the principles of the present invention, which may equally well be employed to roast other products including those mentioned in US. Pat. No. 3,615,668. System 20 includes a roasting or reaction vessel 22 into which unroasted beans are introduced or fed from a gastight lock 24 supplied with grean beans from a storage hopper 26. Lock 24 is employed to maintain isolation between the interior of the reactor and the ambient atmosphere while the solids are introduced and to remove from the solids any air mixed with them.

The solids thus introduced into the vessel are roasted by a fluid which is heated in and circulated through the roasting vessel or roaster by a fluid heating and circulating system 28.

The system also includes a second gastight lock 30 through which roasted beans are discharged from the roasting vessel to a cooling system 32. Lock 30, like 5 lock 24, isolates the roasting vessel from the surroundtransferred to a storage bin 34 or to packaging equipment exemplified by hopper 36.

Another important part of plant 20 is a system 38 which is employed to control the environment in locks 24 and 30 and .to keep air from entering or roasting fluid from escaping from roasting vessel 22 as unroasted solids are introduced and roasted solids discharged. This conserves the roasting fluid and allows the solids to be roasted in an environment of controlled composition or controlled composition and aboveatmospheric pressure.

Other major components of the plant include a novel arrangement 40 (see FIGS. 2 and 4) for driving the moving components of roasting vessel 22 and a control system for regulating the operation of plant 20. The drive arrangement is of particular importance as it permits the uncomplicated locks 24 and 30 to be employed in the stead of the more complex solids transfer devices disclosed in U.S. Pat. No. 3,615,668.

As indicated above, one of the primary components of roasting system 20 is reaction vessel 22. This vessel is illustrated in FIGS. 2 and 3 and described in detail in U.S. Pat. No. 3,615,668 to which reference may be made if deemed necessary.

Referring now to the Figures just mentioned, reaction vessel 22 has a vertically oriented, cylindrical shell 44. As the fluid-solids treatment of this invention can advantageously be carried out under pressure, reaction vessel shell 44 is preferably constructed to withstand pressures up to several hundred pounds per square inch.

For coffee roasting, pressures on the order of 130-150 psig have proved advantageous in many cases. However, as described in my U.S. Pat. No. 3,145,180, pressures on the order of 300 psig can also be used to advantage.

Solidsto be roasted are introduced into roasting vessel 22 through a transfer conduit 46 which extends between supply lock 24 and the roasting vessel. Roasted solids are discharged from the roasting vessel through a discharge transfer conduit 48 which extends through the lower end of shell 44 and communicates with lock 30.

Roasting vessel 22 also includes an inlet 50 for a heated roasting fluid in the lower end of shell 44. The roasting fluid flows upwardly through vessel 22 from inlet 50 and is discharged through an outlet (not shown) into fluid circulating system 28. As the fluid flows through the vessel, it roasts the beans or other solids in the vessel, which are formed into a bed by a solids transfer and fluid distributing arrangement identified generally by reference character 54.

The arrangement 54 just mentioned includes a first, fixed assembly 56 supported from reactor shell 44 and a second assembly 58 rotatable about an axis coincidental with the vertical centerline of roasting vessel 22. Rotatable assembly 58 is employed to transfer the solids from the location at which they are introduced to a location above discharge conduit 48 during the roasting process.

Fixed assembly 56 includes a frustoconical, upwardly and inwardly inclined inner support 60 and a frustoconical, upwardly and outwardly inclined outer support 62. Components 60 and 62 are both supported from a spider 64, the details of which are unimportant in the practice of the present invention. The angle of inclination for both supports will typically be on the order of 60 although this precise angle is not critical.

The assemblyof inner and outer supports 60 and 62 and spider 64 is supported from reactor shell 44 by an annular bracket 66 fixed to the reactor shell, an annular flange 68 on spider 64 being seated on the bracket. Assembly 56 is fixed in place by a fastener 70 which extends upwardly through the bottom of the reaction vessel and is threaded into the spider. An annular seal 72 between bracket 66 and flange 68 prevents the roasting fluid from flowing through the joint between these two components into the upper portions of the reaction vessel.

Also included in fixed assembly 56 is an orifice ring or plate 74, which spans the gap between the lower ends of inner and outer supports 60 and 62. The orifice ring is supported from spider 64 by a support ring 76 to which the ring is secured. Flow passages (not shown) are formed at intervals through support ring 76. As shown in FIGS. 2 and 3, apertures 81 are provided in orifice ring 74 except in locations below bean inlet conduit 46 and above bean discharge conduit 48. The apertures are inclined towards the center of the reaction vessel.

Roasting fluid enters reactor 22 through inlet 50 and then flows .upwardly through the flow passages in support ring 76 and the apertures 81 in orifice ring 74 and the bed of beans, causing the beans to circulate in the pattern shown by arrows 82 in FIG. 2 as they are transferred around vessel 22 by assembly 58. As discussed above and in my issued U.S. Pat. No. 3,345,180, circulation of the beans being roasted is of considerable importance as this provides uniform and intimate contact between the roasting fluid or gas and the solids being processed. Such contact results in the production of a uniform product and also provides versatility, accurate process control, a high rate of heat transfer to the solids, and other advantages.

As indicated above, no apertures are formed in the portion of orifice ring 74 below inlet conduit 46 or above solids discharge conduit 48. In the first of these locations, the orifice ring is solid or imperforate. Accordingly, solids fed into the roasting vessel through inlet conduit 46 may flow into fixed assembly 56 without disturbance by the roasting fluid.

In the portions of orifice ring 74 and support ring 76 above discharge conduit 48, a dump opening 83 is formed. Processed solids flow through the dump opening into discharge conduit 48 for transfer to the cooling vessel 84.

Rotatable assembly 58 includes a vertically extending, cylindrical inner member or sleeve 86 to which a conical cap (not shown) is attached. Fixed to sleeve 86 at equidistant intervals are radial blades or paddles 90. These blades extend from above fixed assembly 56 downwardly into the frustoconically sectioned trough between inner and outer supports 60 and 62. The lower portions of the blades are shaped to match the configuration of the trough.

Blades 90 divide the bed of solids being roasted into a number of distinct portions or segments. By rotating assembly 58, each of these segments or portions of the bed can be caused to move from the position beneath inlet conduit 46 where the segments are formed by the introduction of solids into the reaction vessel through a circular path to opening 83, where the solids are dumped into discharge conduit 48.

Sleeve 86 is rotatably supported from the spider 64 of fixed assembly 55 by a pivot member 92. This member extends upwardly through and is fixed to the sleeve in the manner described in US. Pat. No. 3,615,668.

Fixed in the lower end of sleeve 86 is an internal ring gear 102. This gear, sleeve 86, and blades 90 are rotatably supported from the uppermost member 106 of spider 64 by bearings 108, which will typically be of the ball type. An annular seal 110 between spider member 106 and ring gear 102 assists in confining the roasting fluid to the chamber between movable assembly 58 and reaction vessel shell 44 in which the roasting occurs.

As indicated previously, movable assembly 58 is rotated by drive arrangement 40. Drive 40 includes a pinion 112 in mesh with ring gear 102. The pinion is fixed to a shaft 114 which extends downwardly through a fitting 116, a sleeve 118, and a substantially gastight fitting 120 to the exterior of reaction vessel 22. Fixed to the lower end of shaft 114 is a gear 122 driveconnected as by a chain 124 to a pinion 126. This pinion is fixed to the output shaft 128 of a drive motor 130.

Referring now to FIG. 4, the drive 40 for motor 130 also includes a control system 132 for regulating the motor operation. More specifically, it is the function of control system 132 to so regulate the operation of motor 130 as to alternately advance or rotate assembly 58 through a preselected angle and then halt it for a period of specified duration.

As shown in FIG. 4, motor 130 is connected across a source of operating voltage 134 by leads 136 and 138. lnterposed in lead 136 is the normally open contact 140 ofa relay 142 which also has a coil 144. With relay 142 deenergized, no power is supplied to motor 130.

Relay coil 144 is also connected across power source 134 by lead 138 and by leads 146, 148, and 150. The latter two leads are connected through a normally open switch 152 having an actuator 154 to which a cam follower 156 is attached. Accordingly, this circuit is normally not energized.

Cooperating with cam follower 156 is a disclike cam 158. The cam is secured to the timing shaft 159 of a conventional timing device 160, which also includes a motor 161 for rotating shaft 159. Motor 161 is connected across power source 134 by leads 136 and 138 and by leads 162 and 164.

As shaft 159 and cam 158 rotate, a depression 166 in cam 158 moves opposite cam follower 156; and the cam follower drops into this depression. This displaces switch actuator 154, allowing switch 152 to close and connect relay. coil 144 across power source 134. As a result, the relay is energized, thereby closing normally open relay contact 140. This, in turn, connects motor 130 across power source 134, energizing the motor and causing it to rotate assembly 58 through the drive train 40 described previously.

Shortly after it falls into cam depression 166, the follower 156 rides out of the depression, opening switch 152. However, relay coil 144 is kept energized through a holding circuit including leads 136, 146 and 168 normally closed switch 170, and leads 172 and 138. Accordingly, motor 130 continues to operate and rotate movable assembly 58 until switch 170 is opened.

This is accomplished by an eccentric cam 174 and a cam follower 176. Eccentric 174 is mounted on the pinion 126 attached to the output shaft 128 of drive motor 130. Cam follower 176 is rotatably supported as by bracket 180 from the actuator 182 of switch 170; and, with assembly 58 stopped, it is in the position illustrated in FIG. 4, holding switch 170 open.

As motor output shaft 128 rotates, the follower drops off eccentric cam 174 and allows actuator 182 to move and close switch 170 so that the holding circuit described above can be completed. After one full revolution, cam 174 again engages follower 176, displacing actuator 182 and opening switch 170. This deenergizes relay 142, relay contact 140 opens, motor 130 is deenergized, and the movement of rotatable assembly 58 ceases.

FIG. 5 is a timing chart in which the movement of rotatable assembly 58 in the processing cycle is shown. In a typical cycle, the advance of assembly 58 will take on the order of five seconds; and the assembly will then be halted for about 15 seconds. The assembly will typically be advanced about 20.

The duration of the roasting cycle is of course dependent on the speed of rotation of camshaft 159 the solids always move in the same numberof increments through the same annular path; and the speed of rotation of the camshaft determines the frequency with which assembly 58 is advanced to incrementally displace the solids. The duration of the roasting cycle can accordingly be readily varied by changing the speed of camshaft rotation (in a typical timing device, this is easily accomplished by changing the gears in the drive train (not shown) between the camshaft and timer motor). For a four minute roast, for example, camshaft 159 of one plant of the type described herein is made to rotate once every 15 seconds. It rotates once every 16.9 seconds for a 4.5 minute roast and once every 18.75 seconds for a five minute roast.

As reaction vessel 22 is designed for continuous as opposed to batch-type operation, the beans to be roasted must be introduced into the reaction vessel through a device capable of feeding the beans into the reactor without interrupting the roasting process. In addition, for a satisfactory roast, this must be accomplished in such a manner that no air will be admitted into the roaster and so that air mixed with the beans being introduced can be separated from them. Otherwise, there may be unwanted oxidation of the beans being roasted. Also, to make the system economically practical, the feed device must prevent the inert gas within the reaction vessel from flowing out of it as the beans are introduced because of the expense of the inert roasting fluid.

Similar provisions must be made for discharging the roasted beans from the reaction vessel. That is, this operation must be carried out without interruption of the roasting process and without a significant flow of air into or roasting fluid out of the reaction vessel.

As indicated above, because the bed of solids is alternately advanced and halted by drive 40, the relatively simple air lock arrangement illustrated in FIG. 1 may be employed for these purposes. More specifically, lock 24 is a gastight, hopper-like component and is supplied with the beans or other solids to be roasted, typically from a green bean storage bin 26 as discussed above. As shown in the drawing, the beans are fed from bin 26 through a conventional feeder valve 184 into a pneumatic feed line 185. A blower 186 connected to the feed line by air line 187 forces the beans through the feed line to a hopper 188. From here the beans flow through conduit 190 into lock 24.

Referring now to both FIGS. 1B and 5, a valve 192 is interposed in lock supplying conduit 190, and a valve 194 is disposed in the conduit 46 through which the beans to be roasted are transferred from lock 24 to roasting vessel 22. Initially, valve 194 is closed; and valve 192 is opened, allowing the beans to flow into lock 24. Valve 192 is then closed, isolating the look from both the roasting vessel and the ambient surroundings. The lock is then evacuated to remove from the beans any air mixed therewith. As mentioned above, this is important because it allows the beans to be roasted in an environment of controlled composition in which they will not be subject to oxidative degradation.

Evacuation of lock 24 is accomplished by opening a valve 196 in a vacuum line 198 connected to roasting vessel 22 by line 200 and through line 202 to a vacuum accumulator 204. The latter is in turn connected through line 206 to a vacuum pump 208. Accordingly, with valves 192 and 194 closed and valve 196 open, the air in lock 24 flows through lines 198, 200, and 202 into accumulator 204 from which it is evacuated by pump 208. The foregoing sequence of events is shown in the timing diagram of FIG. 5 as steps 1 and 2.

It is not essential that a vacuum accumulator be used. However, this is preferred as it permits a much small and correspondingly lessexpensive pump to be used.

Specifically, a complete cycle of loading and unloading the reaction vessel occupies only approximately 15-20 seconds, and the step of evacuating lock 24 must be accomplished in 2-3 seconds. If an accumulator is not employed, a pump having a sufficiently large capacity to empty lock 24 in this short period must be provided. On the other hand, if an accumulator is employed, a much smaller pump can be used and operated continuously during the cycle to evacuate from the accumulator the air discharged into it.

At the end of the evacuation step, valve 196 is closed and the pressure in lock 24 equalized with that in the roasting vessel by filling the lock with roasting fluid (typically nitrogen) to system pressure. This is accomplished byopening a valve 209 and pumping nitrogen into the lock from a tank or accumulator 210 by a compressor 212. More specifically, nitrogen in tank 210, typically at approximately atmospheric pressure, is withdrawn through line 213 by the compressor and compressed to system pressure. Valve 209 is interposed in a'line 216 connected between the forementioned line 200 and a line 218 which is connected by line 220 to compressor 212. Accordingly, when valve 209 is opened, the compressed nitrogen flows through filter 221 and line 220 into the lock until the system pressure is reached (in a typical application of the invention, the pressure in the lock at the start of the nitrogen filling step will be on the order of two inches of mercury). As shown by FIG. 5, this step is also typically accomplished in only slightly more than two seconds.

After pressurization, valve 209 is closed and valve 194 opened. This allows the deareated beans to be discharged by gravity from lock 24 into the roasting vessel and into the space between two adjacent blades 90 of rotatable assembly 58 to form one segment of the bed of solids.

To complete the cycle of operation of lock 24, valve 194 is closed and the nitrogen evacuated from the lock and returned to tank 210 to conserve it. As indicated above, this is an important facet of the invention from the point-of-view of operating economy.

It has also been found that significant operating economies can be achieved by removing the nitrogen from lock 24 in two stages. In the first stage, the lock at system pressure, typically on the order of psig, is connected to tank 210 by opening a valve 222 in a branch line 224 connected through line 200 to lock 24 and through lines 226, 228, and 230 to tank 210. The bulk of the nitrogen in lock 24 flows into tank 210 under its own pressure in this step. As shown by FIG. 5, this initial venting step will typicallybe completed in about five seconds.

In the second stage of the nitrogen removal step, the remaining nitrogen in the lock is evacuated by closing valve 222 and opening valve 232 in a branch line 234. This connects lock 24 through line 200, line 234, and line 236 to nitrogen accumulator 238. The accumulator is maintained at a high vacuum (typically on the order of two inches of mercury) by constantly operating vacuum pump 240, which is connected to the accumulator by line 242. Accordingly, there is a rapid of flow of nitrogen from lock 24 into-accumulator 238, this second stage of the evacuation step typically being accomplished in two-three seconds.

As shown in FIG. 1B, pump 240 propels the nitrogen thus returned to accumulator 238 through line 244 into line 230 and thence back into tank 210.

As in the case of the air evacuating system, the accumulator is not essential. However, it is preferred that an accumulator be employed for the reasons discussed in conjunction with the air evacuation system.

Following the evacuation of nitrogen from lock 24, valve 232 is closed; and valve 192 is opened. This completes the cycle and readies lock 24 for a further charge of solids to be roasted.

Referring still to FIGS. 1A and 1B, the system 28 provided in plant 20 for heating and circulating the inert roasting gas or fluid includes a main loop 246. Interposed in loop 246 are a circulator 248 for circulating the heated gas through system 28 and reactor 22, a direct fired heater 250 for the gas, and a chaff separator 252. Also included in main loop 246 on the discharge side of reaction vessel 22 is a valve 254 which can be opened to vent system 28, the reaction vessel, and the system 38 which supplies fluid to the various locks and closed to isolate the vessel and fluid systems from the ambient atmosphere.

Adjacent valve 254 is a valve 256 which can be opened to charge the system with the roasting fluid. To make repairs, for example, the roasting fluid can be vented from plant 20 through valve 254 into a suitable receiver. Upon resuming operation air can be purged from plant 20 by leaving valve 254 open and introducing roasting fluid through valve 256 to sweep air from the system (air can also be evacuated by connecting valve 254 to a vacuum producer). The system can then be recharged through valve 256. The system can be similarly purged and filled with roasting fluid on initial start-up.

A pressure relief valve 258 is located beside valve 256. As it is connected to loop 246 by line 259, valve 258 prevents excessive pressure build-up in fluid system 28 and in roasting vessel 22. It also prevents excessive pressure from building up in the system 38 utilized to fill locks 24 and 30 with roasting fluid by virtue of its connection to line 220 through lines 259 and 260.

System 28 additionally includes a condensor 261 and a separator 262 by which water may be recovered from the recirculated roasting fluid to maintain the moisture content of the fluid at a specified level and a main flow control valve 264 for regulating the rate-of-flow of the roasting gas.

System 28 is similar to the corresponding fluid heating and circulating system described in U.S. Pat. No. 3,615,668and possesses the advantages of the latter. These include simplicity and low initial and operating costs, due both to the relatively small volume of roasting fluid required and the fact that a relatively simple,

direct fired heater can be used.

As shown in FIG. 1, blower 248 circulates the roasting fluid at a rate determined by the positioning of valve 264 through line 266 to heater 250 where the fluid is heated to the desired temperature, typically on the order of 400F, or higher. From here the heated fluid flows through line 268 to roasting vessel 22 and then through the latter in the manner described previously. The roasting fluid, then at a lower temperature and having admixed therewith moisture and other volatiles evolved from the beans during the roasting process, foreign matter, etc. flows through line 270 to chaff separator 252, which is of conventional construction and accordingly will not be described in detail herein. Here chaff and other foreign material is separated from the roasted solids. The cleaned roasting fluid flows from the chaff separator through line 271 back to blower 248 to complete the cycle.

Because system 28 is pressurized and filled with inert fluid, there is interposed in the chaff discharge or dump conduit 272 from the chaff separator an arrangement which allows foreign material to be discharged without a significant flow of air into or inert gas from the separator. This arrangement preferably includes a lock 274 of the same type as the lock 24 described previously. A valve 276 in chaff dump conduit 272 is normally open, and lock 274 (which is first evacuated) is at the same pressure as chaff separator 252. Accordingly, foreign materials separated in the latter fall by gravity into lock 274.

When lock 274 is full, valve 276 is closed; and a valve 278 in line 228 is opened. This connects the lock through lines 282, 228, and 230 to tank or receiver 210.

A valve 283 in a line 284 connected between line 228 and pressure relief line 260 to prevent excessive pressure buildup in chaff separator 252 is also closed. This keeps the fluid in circulating system 28 and in the pressure relief line from flowing back to tank 210 through lines 284, 228, and 230.

With valves 276 and 283 closed and valve 278 open, the roasting fluid flows back to tank 210 until the pressure in the lock reaches atmospheric pressure. Next, a valve 285 in the discharge conduit 286 from lock 274 is opened; and the chaff flows by gravity from the lock. As the pressure on both sides of the lock is equal at this point, there is no appreciable flow of roasting fluid from or flow of air into lock 274. After the lock is emptied, valves 285 and 278 are closed and valves 276 and 283 opened; and the collection of chaff in look 274 is then resumed.

As mentioned above, moisture evolved in the roasting process must be continuously removed from the recirculated roasting gas in typical applications of my invention to prevent the moisture content of the latter from exceeding a preselected level. Regulation of the moisture level is accomplished by circulating a portion of the roasting gas through condensor 261 and separator 262 to remove excess moisture from the recirculating fluid. A valve 288, typically automatically controlled (the control arrangement is not shown), is preferably provided to regulate the volume rate-of-flow of gas from line 266 through line 290 to the condensor and, accordingly, the amount of moisture which is removed.

Condensor 261 is of conventional construction and will not be described in detail herein. Briefly, however, it includes a shell 291 housing a coil (not shown) to which a coolant is circulated by line 292 and from which the coolant is discharged through line 293 at a rate controlled by a valve 294 in the coolant discharge line. The roasting fluid flows through the coil and the coolant through shell 291 over the coil. This lowers the temperature of the roasting fluid, condensing the water vapor in it.

From the condensor the roasting fluid with its burden of condensed moisture flows through line 295 to moisture separator 262, which may also be of conventional construction. Here, the condensed moisture is separated and discharged through a trap 296 which keeps air from flowing into the fluid circulating system.

The roasting fluid from which the moisture has been separated flows through line 298 to line 271 where it is mixed with the roasting fluid flowing directly to blower 248 through the latter. This permits the moisture content to be accurately controlled.

In some cases the moisture content of the fluid supplied by blower 248 to roasting vessel 22 may be too low rather than too high. To cover this contingency, a pump 300 connected to a source of water (not shown) through line 302 and to fluid line 271 by a line 304 may be provided. If the moisture content of the recirculated fluid becomes too low or is too low on start-up, for example, pump 300 can be energized (preferably automatically) to pump water into line 271 and bring or restore the moisture content of the recirculated fluid to the desired level.

Referring again to FIGS. 1 and 5, l have thus far described how the beans or other solids are introduced into and roasted in roasting vessel 22. At the completion of the roasting step, the roasted solids are discharged through dump opening 83 into transfer conduit 48 and through the transfer conduit into discharge lock 30 as discussed above. The discharge lock, which may be of the same construction as feed lock 24, is also connected to the cooler 84 of cooling system 32 by a transfer conduit 306.

To transfer roasted solids from roasting vessel 22 to lock 30, a valve 308 in transfer conduit 48 is opened, filling lock 30 with roasting fluid and equalizing the pressure in the lock with that in the roasting vessel. This allows the beans flowing into conduit 48 through dump opening 83 to fall by gravity into the lock. Valve 308 is then closed, isolating the lock.

The nitrogen or other roasting fluid is then evacuated from the lock to conserve it, preferably in two stages as discussed above in conjunction with feed lock 24. Specifically, valve 310 is first opened. This connects lock 30 with the atmospheric pressure tank or receiver 210 through lines 312, 224, 226, 228 and 230. The nitrogen in look 30 accordingly flows under its own pressure into tank 210. As shown in FIG. 5, this stage of the nitrogen '13 evactuation step typically takes on theorder of two to three seconds.

Valve 310 is then closed and a valve 314 opened,

connecting the lock through lines 312, 234, and236 to the evacuated nitrogen accumulatingstank or receiver 238. This step, which will also typically take on the order of two seconds, reduces the pressure in the'lock to on the order of two inches of mercury.

Valve 314 is then closed and the valve 3l6in transfer conduit 306 opened. This allows the beans or other solids to flow by gravity from'lock 30 through conduit 306 into cooler 84. i

In a typical application of the present invention, cooler 84 will be filled with air at slightly above atmospheric pressure. To keep this air from the roasting vessel, valve 316 is next closed andthe air evacuated-from the lock by opening valve 318. Thisconnects .the interior of the lock through lines 312, 198 and 202 to the evacuated air receiver 204. This evacuation step also occurs in two to three seconds.

Valve 318 is then closed and lock 30 repressurized with roasting fluid by opening valve 320. Thisconnects the lock to the outlet side of compressor 212 through lines 220, 218, 216 and 312. Valve 320 is then closed and valve 308 opened to complete the cycle.

Important to the successful operationof roasting system 20 is the particular type of valve employed to control the flow of solids through locks 24 and 30 and to isolate these locks from the roasting vessel, cyclone 188, and cooler 84. All four of these valves (192, 194, 308, and 316) may be identical and may be of the exemplary construction shown in FIG. 7 of the drawing. Similar valves can also be used to advantage to control the discharge of chaff from lock 274 and to isolate this lock because the valves associated with it are also contacted by high temperature gases and abrasive substances.

Referring now to the Figure just mentioned, the valve therein illustrated and identified by reference character 324 numbers among its main components a generally Y-shaped valve body 326 provided with conventional mounting flanges 327. Housed in the valve body are a removable valve seat 328 and a valve member 330 supported on a valve stem 332. The valve also includes a fluid-actuated cylinder 334 for moving valve member 330 into contact with seat 328 to close the valve and away from the seat to open it.

Valve body 326 has an axially aligned inlet 336 and an outlet 337. A flow passage 338 through the valve provides fluid communication between the inlet and outlet.

Valve seat 328 surrounds flow passage 338 and is seated on an annular ledge 340 in a valve body 326 with its longitudinal axis 342 inclined at an angle of approximately 40 to the axis 344 along which inlet 336 and outlet 337 are aligned.

As shown in FIG. 7, a flat, circular gasket 346 is interposed between valve seat 328 and valve body 326. This gasket keeps fluid from leaking past the valve seat when the valve is closed.

Valve seat 328 is retained in place by radially extending fasteners 348 which are threaded through valve body 326 and extend into a peripheral groove 350 in the valve seat. 3

in assembling the valve seat to valve body 326, gasket 346 and valve seat 328 are put in place and retained by loosely tightening retainers 348. Cylinder 334 is then actuated-to move valve member 330 against and load the valve seat. This compresses gasket 346 and forms a tight seal.

Retainers 348:are then tightened. Asshown in FIG. 7, the peripheral groove 350 in the seat is located further from the edge 352 of the seat facing ledge 340 than that edge 354 facing valve'member 330. Accordingly, as retainers 348 are tightened, the valve seat is forced still tighter against gasket 346 to perfect the seal between the seat and valve body 326.

Referring still to the drawing, valve member 330 is of the disc type. It has a diameter exceeding that of the central aperture 356 through valve seat 328. Accordingly, when the valve member is moved against the seat toform a seal therebetween, flow through passage 338 is precluded.

Valve member 330 has a central bore 358 through which an elongated valve stem member 360 extends. A clearance is provided between stem member 360 and valve member 330 so that the valve member can tilt on theorder of two or three degrees relative to the stem.

through the bore 358 in valve member 330 when the valve is closed.

As shown in FIG. 7, stem member 360 is axially aligned with and threaded into a second valve stem member or adapter 367. One end of the valve stem adapter terminates in a radially extending abutment 368. Valve member 330 is resiliently biased against this abutment by Belleville springs 370 and 372, a washer 374, and a retainer 376 which can be threaded along valve stem member 360 to vary the force with which valve member 330 is biased against adapter 367 A second retainer 378 is threaded on stem member 360 adjacent retainer 376 to lock the latter in the position to which it is adjusted.

As shown in FIG. 7, valve stem 332 is axially aligned with the longitudinal centerline 342 of the valve seat. It is moved in a rectilinear path along this axis by fluidactuated cylinder 334 to move valve member 330 toward and away from seat 328 in a path extending in the same direction as centerline 342.

As valve member 330 is moved toward seat 328, valve member surface 380 engages an annular knifeedge projection 382 formed on seat 328 and facing the valve member. This edge is preferably made with a small radius to keep it from being nicked or otherwise damaged. It permits high unit contact pressures to be established between the valve member and the valve seat without the exertion of excessive pressures on either component. At the same time, the valve member can tilt relative to stem 332 as necessary to make the contact pressure generally uniform over the entire area of contact.

The formation of a tight seal is important. especially in applications such as roasting system 20, as pressures of up to several hundred pounds per square inch operating in a valve unseating direction may be present. Also, because of the knife edge on the valve seat, foreign material will not keep the valve from being completely closed. Any foreign matter present on the seat or surface 380 of the valve member will simply be sheared as the valve member is moved into engagement with seat 328.

The valve arrangement just discussed also eliminates the need for close tolerances, making the valve cheap to construct. This is a feature not possessed by other high-pressure service valves. They require precision fitting which is expensive. Also, the valve member usually extends into the seat to form the seal in such valves, and this means they can be easily scratched or otherwise damaged if abrasive material is present as it would be in an installation such as system 20.

Referring again to the drawing, the adapter 367 of valve stem 332 is threaded into the free end 384 of the piston rod 386 of fluid-actuated cylinder 334. This cylinder may be of conventional construction and is mounted on valve body 326 with the axial centerline of the piston rod forming an extension of the longitudinal axis 342 of valve seat 328.

One suitable, commercially available fluid-actuated cylinder which may be employed is an Ortman-Miller Series 4L, Style B hydraulic cylinder. There are of course a number of other, commercially available equivalents which may be used instead.

As shown in FIGS. 7 and 6, cylinder 334 includes, in addition to piston rod 386, a barrel 388 housing a piston 390 to which the piston rod is fixed and cylinder heads 392 and 394 with piston rod 386 extending through the latter.

Cylinder 334 is operated in conventional fashion. That is, by admitting fluid through line 396, pistion 390, piston rod 386, and valve stem 332 can be moved in the direction shown by arrow 398 in FIG. 7 to move valve member 330 away from seat 328 and open the valve. Conversely, by admitting operating fluid to the cylinder through line 400, piston rod 386 and valve member 330 can be moved in the opposite direction as shown by arrow 402 to move the valve member against seat 328 and close the valve.

Referring again to the drawing, valve body 326 has an open end 404 in the vicinity of valve member 330 and fluid-actuated cylinder 334. Fitted in opening 404 is a cover 406 secured in place as by cap screws 408, which extend through the cover and are threaded into the valve body.

In the illustrated embodiment of the invention, fluidactuated cylinder 334 is mounted on cover 406 as by headed studs 410 which extend through flanges 412 on cylinder head 394 and are threaded into the cover.

The mounting of fluid-actuated cylinder 334 on cover 406 is of considerable importance from a practical point-of-view. As will be apparent from FIG. 7, this permits the fluid-actuated cylinder, the valve stem, and the valve member to be simultaneously removed from the installation in which the valve is incorporated for servicing simply by removing retainers 408. At the same time, this also affords access to valve seat 328, which can be readily removed through opening 404 after loosening retainers 348.

Referring still to FIG. 7, communication between the interior and exterior of valve body 326 for valve stem 332 and pistion rod 386 is provided by a central aperture 414 through cover 406. To keep fluid from leaking past piston rod 386 through this aperture to the exterior of the valve body, stem packing consisting of Teflon V" rings 416 is disposed in an enlarged diameter portion 418 of the bore 414 around piston rod 386. The packing is retained in place by an annular ledge 420 in cover 406 and by a conventional, cylinder packing flange 422, which extends into recess 418 into engagement with the V rings and is secured to cover 406 as by cap screws 424.

An O-ring or comparable seal 425 .keeps fluid from leaking past the periphery of the cover to the exterior In valve 426, the valve seat 428 is a ringlike member I have a flat sealing surface 430 rather than a knife edge. The valve seat is retained in place by a washerlike seat retainer 432 and cap screws 434 (only one of which is shown), which press the valve seat against an annular seating ledge 436 in valve body 438.

To form a tight seal with this type of valve seat, an annular knife edge 440 with a small radius is formed on the side 442 of valve member 444 which faces valve seat 428. Knife edge 440 is dimensioned to engage the sealing surface 430 of seat 428 and provide between the seat and valve member a tight seal of the character described above.

Valve 426 also differs slightly in the manner in which the fluid-actuated cylinder 446 is supported from the valve body. In this case, cap screws 448 extending through a flange 450 on cylinder head 452 connect the fluid-actuated cylinder to cover member 454 through a pilot flange 456 and an insulator 458.

The particular system employed to control the operation of valves 192, 194, 276, 285, 308, and 316 is not critical and may be varied as necessary for different applications of the invention. One suitable system, however, is shown schematically in FIG. 6 and identified by reference character 460. This system, which is of the hydraulic type, includes a reservoir 462 (shown at different locations in FIG. 6 for the sake of convenience), a hydraulic pump 464, and a conduit system identified generally by reference character 466. A check valve 468, a pressure relief valve 470, an accumulator 472, and a bypass with a filter 474 are incorporated in the conduit system in accord with customary practice.

In FIG. 6, the fluid-actuated (here hydraulic) cylinders of the six valves associated with locks 24, 30 and 274 are identified by the same number as the valve followed by the letter C. The flow of hydraulic fluid to the cylinders to open and close the associated valves is controlled by four 4-way, solenoid-operated control valves 476, 478, 480, and 482.

Although it is not necessary, the chaff is discharged from separator 252 on the same cycle that roasted solids are discharged from reaction vessel 22. Accordingly, cylinders 276-C and 308-C are connected in parallel to reservoir 462, and operating fluid is directed to them by a single control valve (480) to open and close valves 276 and 308 in unison.

Valves 285 and 316 are, of course, also operated in unison. They, too, are connected in parallel to reservoir 462. The fluid is directed to the cylinders 285-C and 316-C of these two valves by control valve 482.

The manner in which valves 476 482 control the operation of the fluid-actuated cylinders is conventional and thought to be apparent from FIG. 6 and will, accordingly, not be described in great detail herein.

Briefly, however, and taking the control exerted by valve 480 as an example, with the solenoid 480-R of the control valve deenergized, the valve is as shown in FIG. 6. It therefore directs operating fluid under pressure to the left-hand faces of the pistons 390 in cylinders 276-C and 308-C while the fluid on the opposite sides of the pistons is returned to reservoir 462 through the control valve. This causes the pistons of the two cylinders to move to the right as shown in FIG. 6, extending the pistion rods 386 from the barrels of the cylinders. This closes the valves. 4

To open valves 276 and 308, the solenoid 480-R of control valve 480 is energized. This shifts the control valve member to the right as shown in FIG. 6, connect ing the reservoir with cylinders 276-C and 308-C through valve 480 as shown by arrows 484 and 486. This reverses the direction of flow of operating fluid to the cylinders so that the fluid under pressure is applied to the right-hand sides of the pistons 390 and the fluid on the opposite sides of the pistons returned to the reservoir. This causes the pistons to move to the left as shown in FIG. 6, retracting the piston rods and opening valves 276 and 308.

The manner in which the other four fluid-actuated motors are operated is essentially the same as that just described.

Referring now to both FIGS. 4 and 6, the energization and deenergization of each control valve solenoid 476-R. 478-R, 480-R, and 482-R is controlled by a cam and a microswitch identical to those identified by reference characters 158 and 152 in FIG. 4. These cams are mounted on the timing shaft 159 of timing device 160 alongside cam 158. The cam slots in the control valve cams are dimensioned and orientedso that they will energize and deenergize the solenoids in a pattern which will open and close the control valves as shown in FIG. 5.

To avoid unnecessary duplication and make the drawing clearer, and because the solenoids are simply connected in series with the associated switches, the additional cams and switches and the leads connecting them to the solenoids have not been shown.

Returning again to FIG. 1B of the drawing, the remaining major system of plant 20 is the cooling system 32 to which the roasted solids are transferred from roasting vessel 22 through discharge lock 30. The main component of this system is cooling vessel 84 which may be of any desired construction. Typical of the coolers-which may be employed is the rotary drum type reactor or cooling vessel described in my US. Pat. No. 3,345,180. For reasons of economy, air will typically be employed as the cooling medium; and a blower or circulator 488 will be incorporated in system 32 to circulate the air through cooling vessel 84.

A low overpressure will normally exist in cooler 84. Accordingly, if the cooled beans are discharged directly from the cooler to atmospheric pressure, the beans and chaff in the system may blow about. To avoid this, the beans may be discharged from the cooler through a lock of the type described above (not shown), for example.

As shown in FIG. 1B, solids cooling system 32 also includes a water supply line 490 connected interiorly of cooler 84 to conventional spray nozzles 492. As discussed in detail in U.S. Pat. No. 3,345,l80, a spray can be employed to quench the roast and thereby prevent overroasting and to minimize roasting losses. A valve 494 is incorporated in the water supply line 490 to regulate the spray rate.

A chaff separator (not shown) may be added to cooling system 32 to separate foreign material from the air discharged from vessel 84. This separator may be of the same type as chaff separator 252.

As shown in FIG. 1, the cooled beans can be transferred through conduit 496 to packaging equipment hopper 36. Alternatively, they may be directed through conduit 496 and conduit 498 to the roasted beans storage bin 34.

To direct the solids to storage bin 34, a valve 500 in a line 502 connected between storage bin 34 and packaging equipment hopper 36 is opened and a second valve 504 in the same line closed. This connects bin 34 with the inlet of conveyor blower 186 through lines 502 and 506, creating a vacuum in the storage bin. This causes air to flow from cooling vessel 84 to bin 34 through conduits 496 and 498 and transport the roasted solids from the cooling vessel to the bin.

To convey the solids to packaging equipment hopper 36 instead of bin 34, valve 500 is closed and valve 504 opened. This connects the inlet of blower 186 to hopper 36, lowering the pressure in it and thereby causing the beans to be pneumatically conveyed from the cooling vessel to the hopper.

The invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The present embodiment is therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description; and'all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.

What is claimed and desired to be secured by Letters Patent is:

1. Apparatus for roasting coffee and comparably processable solids, comprising a roasting vessel having a shell and means in said shell for supporting a bed of solids to be roasted; means for introducing a heated roasting fluid into the roasting vessel and for effecting a flow of the fluid through the vessel and the bed of solids therein; and means for so introducing solids into and removing them from the roasting vessel as to substantially preclude the flow of air into or the flow of heated fluid from the roasting vessel and as to separate from the solids as they are introduced any air mixed therewith, whereby said solids can be roasted in an atmosphere of controlled composition and the loss of heated fluid from the roasting vessel during the introduction and removal of the solids can be abated, said lastmentioned means comprising a feed lock for solids to be roasted having an inlet and an outlet communicating with the interior of the roasting vessel, a discharge lock for roasted solids having an inlet communicating with the interior of the roasting vessel and an outlet, and valves for controlling flow through the inlets and outlets of said locks, each said valve comprising a valve body having an axially aligned inlet and outlet therein; a passage in the valve body providing communication between said inlet and said outlet; a centrally apertured valve seat in said valve body between said inlet and said outlet and surrounding the passage therebetween whereby fluid must flow through the central aperture in said valve seat from said inlet to said outlet, said valve seat being inclined relative to the axis along which the inlet and outlet are aligned; a valve stem mounted for rectilinear movement in said valve body toward and away from the valve seat; a valve member mounted on and movable with said stem, said valve member being engageable with said valve seat to preclude the flow of fluid through the passage between the inlet and outlet, a first of said valves having the outlet thereof communicating with the inlet to the feed lock, a second of said valves having its inlet communicating with the outlet from the feed lock and its outlet communicating with the interior of the roasting vessel, a third of said valves having its inlet communicating with the interior of the roasting vessel and its outlet communicating with the inlet to the discharge lock, and a fourth of said valves having its inlet communicating with the outlet from the discharge lock.

2. The apparatus of claim 1, wherein all of said valves are so oriented that solids can flow through the passages in the valve bodies thereof by gravity.

3. The apparatus of claim 1, wherein each of said valves includes a fluid-actuatedcylinder for moving the valve member of the valve toward and away from the valve seat thereof, the fluid-actuated cylinder having a piston rod connected to the valve stem of the valve.

- 4. The apparatus of claim 1, together with means including said first and second valves for sequentially isolating said feed lock from the roasting vessel, introducing solids to be roasted into said lock, isolating the lock from the ambient surroundings, evacuating the lock, filling the lock with roasting fluid, and providing communication between the lock and roasting vessel to transfer the solids from said lock to said vessel; means including said third and fourth valves for sequentially isolating the discharge lock from the surrounding environment, evacuating the lock, filling the lock with roasting fluid, providing communication between the lock and roasting vessel to transfer roasted solids from the roasting vessel to the lock, and evacuating the lock; and means for thereafter emptying the solids from the lock.

5. The apparatus of claim 4, wherein the means for evacuating air from the feed and discharge locks comprises a vacuum producer, conduit means connecting said locks to said vacuum producer, and valve means operable to provide communication through said conduit means between said locks and said vacuum producer and wherein the means for filling said locks with roasting fluid and for evacuating roasting fluid therefrom comprises a roasting fluid supply system which includes means for circulating the roasting fluid through said system to said locks at a pressure sufficiently high erable with said shell, the roasting vessel shell having a cylindrical configuration, said movable assembly being mounted for rotational movement about a vertical axis and including means for dividing the bed of solids into a plurality of generally discrete segments, and said apparatus including means for periodically advancing the movable assembly which comprises an electric motor, means drive-connecting said motor to said movable assembly, and control means for alternately energizing said motor for periods of designated duration, whereby said assembly is alternately advanced to transfer the solids in the bed thereof from a first location to a second location as they are roasted by the heated fluid circulated through them and halted with a segment of the bed containing roasted solids at said second location to discharge said solids from the bed and with the space occupied by a previously occupied segment of the bed at said first location for replacement of said lastmentioned segment of the bed with unroasted solids.

7. The apparatus of claim 6, wherein said control means includes a first circuit for connecting said motor across a source of operating voltage, a relay having a coil and a normally open' contact in said first circuit, a second circuit for connecting said relay coil across said power source, a switch having an actuator and a normally open contact in said second circuit, timing means for periodically displacing said actuator and effecting a closing of the switch contact for a period sufficiently long to energize the relay coil and thereby cause its contact to close to energize the motor, a holding circuit including a normally closed switch connected across to pressurize said locks to a pressure equal to that in the roasting vessel, a first means for evacuating roasting fluid from the locks and returning it to the supply system to reduce the pressure in said locks to a preselected level, a second means for evacuating substantially all of the remainder of the roasting fluid from the locks and returning it to the supply system, conduit means connecting said locks to said circulating means and to said first and second fluid evacuating means and valve means in said conduit means for providing selective communication from said locks through said conduit means to said fluid circulating means and to said first and second fluid evacuating means.

6. The apparatus of claim 1, wherein the means for supporting the bed of solids comprises the roasting vessel shell and fixed and movable assemblies in and coopthe relay coil for keeping the relay energized, and means operable after rotation of the movable assembly through a predetermined angle to open the normally closed switch and thereby interrupt the supply of power to the electric motor.

8. The apparatus of claim 1, together with means for recirculating the roasting fluid after it flows through the roasting vessel; a chaff separator connected into said means on the downstream side of the roasting vessel; and means for emptying chaff from said separator comprising a third substantially gastight lock and means for sequentially filling said lock with roasting fluid to a pressure substantially equal to the pressure in the chaff separator, providing communication between the separator and lock to allow the transfer of foreign material from the separator to the lock, reducing the pressure in the lock to atmospheric pressure by evacuating roasting fluid from the lock, and providing communication between the lock and a receiver for the foreign material, whereby the lock can be emptied without a significant flow of air into or roasting fluid from the lock.

9. The apparatus of claim 8, further comprising a closed circulation system for the roasting fluid including the roasting vessel and said feed and discharge locks, a pressure relief means operable to vent roasting fluid from the closed circulation system if the pressure therein exceeds a specified level, conduit means connecting the third lock through the means for filling said third lock with roasting fluid to the pressure relief valve, a first valve in said conduit means which can be closed to keep roasting fluid from flowing therethrough into the third lock when said third lock is being evacuated and otherwise opened to provide communication between said third lock and said pressure relief means, and a second valve which can be closed to keep fluid from being pumped out of said third lock.

i i l l 

1. Apparatus for roasting coffee and comparably processable solids, comprising a roasting vessel having a shell and means in said shell for supporting a bed of solids to be roasted; means for introducing a heated roasting fluid into the roasting vessel and for effecting a flow of the fluid through the vessel and the bed of solids therein; and means for so introducing solids into and removing them from the roasting vessel as to substantially preclude the flow of air into or the flow of heated fluid from the roasting vessel and as to separate from the solids as they are introduced any air mixed therewith, whereby said solids can be roasted in an atmosphere of controlled composition and the loss of heated fluid from the roasting vessel during the introduction and removal of the solids can be abated, said lastmentioned means comprising a feed lock for solids to be roasted having an inlet and an outlet communicating with the interior of the roasting vessel, a discharge lock for roasted solids having an inlet communicating with the interior of the roasting vessel and an outlet, and valves for controlling flow through the inlets and outlets of said locks, each said valve comprising a valve body having an axially aligned inlet and outlet therein; a passage in the valve body providing communication between said inlet and said outlet; a centrally apertured valve seat in said valve body between said inlet and said outlet and surrounding the passage therebetween whereby fluid must flow through the central aperture in said valve seat from said inlet to said outlet, said valve seat being inclined relative to the axis along which the inlet and outlet are aligned; a valve stem mounted for rectilinear movement in said valve body toward and away from the valve seat; a valve member mounted on and movable with said stem, said valve member being engageable with said valve seat to preclude the flow of fluid through the passage between the inlet and outlet, a first of said valves having the outlet thereof communicating with the inlet to the feed lock, a second of said valves having its inlet communicating with the outlet from the feed lock and its outlet communicating with the interior of the roasting vessel, a third of said valves having its inlet communicating with the interior of the roasting vessel and its outlet communicating with the inlet to the discharge lock, and a fourth of said valves having its inlet communicating with the outlet from the discharge lock.
 2. The apparatus of claim 1, wherein all of said valves are so oriented that solids can flow through the passages in the valve bodies thereof by gravity.
 3. The apparatus of claim 1, wherein each of said valves includes a fluid-actuated cylinder for moving the valve member of the valve toward and away from the valvE seat thereof, the fluid-actuated cylinder having a piston rod connected to the valve stem of the valve.
 4. The apparatus of claim 1, together with means including said first and second valves for sequentially isolating said feed lock from the roasting vessel, introducing solids to be roasted into said lock, isolating the lock from the ambient surroundings, evacuating the lock, filling the lock with roasting fluid, and providing communication between the lock and roasting vessel to transfer the solids from said lock to said vessel; means including said third and fourth valves for sequentially isolating the discharge lock from the surrounding environment, evacuating the lock, filling the lock with roasting fluid, providing communication between the lock and roasting vessel to transfer roasted solids from the roasting vessel to the lock, and evacuating the lock; and means for thereafter emptying the solids from the lock.
 5. The apparatus of claim 4, wherein the means for evacuating air from the feed and discharge locks comprises a vacuum producer, conduit means connecting said locks to said vacuum producer, and valve means operable to provide communication through said conduit means between said locks and said vacuum producer and wherein the means for filling said locks with roasting fluid and for evacuating roasting fluid therefrom comprises a roasting fluid supply system which includes means for circulating the roasting fluid through said system to said locks at a pressure sufficiently high to pressurize said locks to a pressure equal to that in the roasting vessel, a first means for evacuating roasting fluid from the locks and returning it to the supply system to reduce the pressure in said locks to a preselected level, a second means for evacuating substantially all of the remainder of the roasting fluid from the locks and returning it to the supply system, conduit means connecting said locks to said circulating means and to said first and second fluid evacuating means and valve means in said conduit means for providing selective communication from said locks through said conduit means to said fluid circulating means and to said first and second fluid evacuating means.
 6. The apparatus of claim 1, wherein the means for supporting the bed of solids comprises the roasting vessel shell and fixed and movable assemblies in and cooperable with said shell, the roasting vessel shell having a cylindrical configuration, said movable assembly being mounted for rotational movement about a vertical axis and including means for dividing the bed of solids into a plurality of generally discrete segments, and said apparatus including means for periodically advancing the movable assembly which comprises an electric motor, means drive-connecting said motor to said movable assembly, and control means for alternately energizing said motor for periods of designated duration, whereby said assembly is alternately advanced to transfer the solids in the bed thereof from a first location to a second location as they are roasted by the heated fluid circulated through them and halted with a segment of the bed containing roasted solids at said second location to discharge said solids from the bed and with the space occupied by a previously occupied segment of the bed at said first location for replacement of said last-mentioned segment of the bed with unroasted solids.
 7. The apparatus of claim 6, wherein said control means includes a first circuit for connecting said motor across a source of operating voltage, a relay having a coil and a normally open contact in said first circuit, a second circuit for connecting said relay coil across said power source, a switch having an actuator and a normally open contact in said second circuit, timing means for periodically displacing said actuator and effecting a closing of the switch contact for a period sufficiently long to energize the relay coil and thereby cause its contact to close to energize the motor, a holding circuit including a normally closed Switch connected across the relay coil for keeping the relay energized, and means operable after rotation of the movable assembly through a predetermined angle to open the normally closed switch and thereby interrupt the supply of power to the electric motor.
 8. The apparatus of claim 1, together with means for recirculating the roasting fluid after it flows through the roasting vessel; a chaff separator connected into said means on the downstream side of the roasting vessel; and means for emptying chaff from said separator comprising a third substantially gastight lock and means for sequentially filling said lock with roasting fluid to a pressure substantially equal to the pressure in the chaff separator, providing communication between the separator and lock to allow the transfer of foreign material from the separator to the lock, reducing the pressure in the lock to atmospheric pressure by evacuating roasting fluid from the lock, and providing communication between the lock and a receiver for the foreign material, whereby the lock can be emptied without a significant flow of air into or roasting fluid from the lock.
 9. The apparatus of claim 8, further comprising a closed circulation system for the roasting fluid including the roasting vessel and said feed and discharge locks, a pressure relief means operable to vent roasting fluid from the closed circulation system if the pressure therein exceeds a specified level, conduit means connecting the third lock through the means for filling said third lock with roasting fluid to the pressure relief valve, a first valve in said conduit means which can be closed to keep roasting fluid from flowing therethrough into the third lock when said third lock is being evacuated and otherwise opened to provide communication between said third lock and said pressure relief means, and a second valve which can be closed to keep fluid from being pumped out of said third lock. 